Mixing and blending



-April 5, 193s.

R. JACKSON MIXING AND BLENDING Filed Oct. 22, 1936 fand u W iL/QH,

I Patented Apr. 5, 1938 UNITED STATES MIXING AND BLENDING v Reginald Jackson, Clayton, Mo.,vassignor to Alu@ minum Company of America, Pittsburgh, Pa., a corporation of Pennsylvania Appuestion oetoberzz, 193s, serial No. 107,005

9 Claims.

This invention relates to the mixing and blending of granular or powdered materials, kand specifically to the mixing and vblending ofsuch materials in large quantities such as, for ex- 5 ample, carload lots of l approximately 60,000

pounds.

Heretofore it has been diiilcult to blend or mix together several kinds of granulariorv powdered materials of different characteristics sol intisack of the mixture in a carload shipment would contain identical proportions ofthe several ingredients and be of identical quality. Modern specifications and mass production manufacture require a, mixing apparatusl capable of obtaining and maintaining uniformity throughout a large quantity of mixed materials.

The primary object of the invention is to provide an improved method and apparatus of the character stated which is capable of carrying out a mixing and blending operation with a minimum amount of physical labor.

A further object of the invention is to provide a mixer capable of vconveying material in opposite directions at the same time and in which the material as it travels through the apparatus is automatically divided into several predetermined paths or streams of flow.

A further object of they invention isv the provision of a process whereby granular or powdered materials are mixed or blended more completely in less time than heretofore known. j

A further object of the invention is the provision of a method for mixing materials where- 35 by several portions of the mass, into which it is divided, are conveyed in opposite directions, individual portions being reintroduced to the mass at spaced intervalsjalong the path traversed by the original mass.

40 yA still further object of the invention is toy provide a rotary conveyor having associated therewith means to positively divide the traveling mass into several units and to` direct each such unit along its path of travel. y r

In the accompanying drawing forming a part of this specification, Fig. 1 is aside elevation ofthe assembled apparatus with part oi' the shell broken away, showing a portion Aof the longitudinal conveying mechanism; v

Fig. 2 is a section taken on line II-II of. Fig.j1, showing the scoop feeders;

Fig. 3 is a section' taken on line III- III of Fig. 1, which shows the dual feeding screws, together with one of the central tube discharge 55' units;

mately, so completely, and so uniformly that every Fig. 4 is a section taken on line IV-IV of'Flg.

1, showing a scoop feeder provided with a gate for regulating discharge of the material;

y Fig. 5 is a section takenon line V-V of Fig. l, showing the discharger scoop. .l 5

The apparatusof this invention consists essentially of an external cylindrical drum, relatively long in proportion to its diameter, together with an inner cylindrical drum coaxial with the outer drum. 'The outer drum may be equipped with circular tires and supported on fixed rollers, or the tires and rollers may take the form of suitable gearing.V The particular form of support and power mechanism is immaterial, so long as reversible rotation of the unit about its horizontalA axis is possible.` Both the outer drum and the inner cylinder are provided with helical blades, and for the sake of convenience, will be vhereinafter referred to as helical flights". The term flight will be regarded as defining the particular 20 blading in a predetermined section of the apparatus as, for instance, single helical flight or double helical flight. The inner cylinder is provided With several discharger units forv emptying the material from the inner cylinder intothe outer drum. Suitable scoop feed .anddischarge units are provided at appropriate places in the apparatus for moving the material being mixed from one section of the machinevto another, Aaccording to the direction of rotation of the drum. The outer drum receives` and discharges material through a single feeding and discharging unit which is provided at eitherv end with scoops.

The outer drum in its preferred form comprises an elongated casing I which for clarity'and convenience may be regarded as 4being of three sections, A, B, and Q. Each of these sections extends approximately for a distance of about ,one-third the length'of the outer drum. kInside of and coaxial with the drum is unitarily mounted `a cy.A

, lindrical tube 2 of alength slightly less thanthat of the outerY drum. Likewise, the inner cylindrical .tube may be regarded as comprising three sections, a,.`b, and c. Rigidly secured to the inner surface` of the outer drum are conveying means which, in .the preferred form, are flights. of helical blades. In .section A there is provided a single helical flight; in section B, a double helical flight, and in section C, a triple helicalv flight. Within the innercylindrical tube and rigidly secured thereto are similar flights of helical form: section a, having a single helical flight, section b, a double helical flight, and section c, a`triple helical flight. It is to be noted that the .hand

of these ights is opposite to that of the'hand 455V of the nights oftheouter drum, sothat upon rotation of the drinn, material will be conveyed along the length of the inner cylinder in a direction opposite to that in which it is traveling along the outer drum. Therefore, whether blending or discharging, material is being moved in both the outer drum and inner cylinder at the same time, but in opposite directions.

A charge or batch of material entering the inlet end of the mixer is conveyed along the outer drum from .left torlght (Fig. 1) bythe helical nights secured to the inner surface ,of the outer drum. While passing through section A of the drum, the material may belregard'ed' as. being moved in a single stream". Upon reaching sec# tion B, the double helical nights of blades in .that section divide 'the single stream into two ."streams" of material and `likewise the double stream" passing from section B to sectionC is divided into three streams, due to the triple v helical nights ofthe latter section. Hence, what pwas la' single stream of advancing material in `section A is nowa triple stream" in section C.

At the extremeright-hand end of thev mixer and enclosed within the end of the drum are three'scoop feeders-3. These scoops are of the same hand and are disposed in such a, manner that eachscoop'picks up material which is being conveyed along the outer drum by the triple helical nights and deposits it into the inner cylndrical' tube 2. Within section c of the inner cylindrical tube, the conveying meansare triple helical nights of blading of a hand oppositeto the hand of the nights of the outer drum. Ma-

terial which has been picked up'byv the scoop feed-v the inner cylindrical tube. The material is emptied into the outer drum, where it again resumes its travel toward the right-hand end of the drum. After one "stream of material is emptied into the outerdrum by the discharger between sections b and c, the remaining double stream continues on through' section b until reaching the discharger between'sections a and b. Here,` another* stream is deflected into the outer drum and4 the single remaining stream 4'permitted Vto pass along section a where, upon rreaching the last discharger, itylikewise is emptiedy into thef'outer drum. v

vAt the left-hand end of the machine there is located a feeding and discharging unit A5. A

relatively small feed-and-discha'rge neck 6 is provided on the axis of the drum.` Atpeithe'r end of this neck are scoop'feeders 'I and 8, one being located outside thev drum, the other vwithin the head of the drum. A discharge regulating cate 8 is mounted on'the scoop 8.- These scoop feeders are of yopposite handjso that when rotation of the drum is such that the external feeder 1 is picking up material, the internal scoop feeder 8 will discharge material intothe drum. The conveying element vof the unit 'Q is a single helical screw, and affords appropriate movement of the material from the external feeder into the internal feeder or vice versa, according to the ldirection of rotation of the drum. A gate f |40 serves to permit discharge of the blended material at appropriate times.

Inkoperation, the gate Il is closed and the material to be mixed or blended fed into the supply hopper Ii. The drum is rotated in a direction (counter-clockwise looking `at Fig. 2) such that the material isvpickl'ed up by the external y,scoop feeder and delivered to the inside of the drum. As the material travels through the drum, it is successively dividedinto separatestreams and kcontinues its travel until it contacts the three scoop feeders at the righthand end ofthe machine. Herve each stream is denected 4'into its own separate space which is established bythe triple helical nights within section c of the inner cylindrical tube. The direction of travel of the units mounted on the inner tube serve to each discharge one stream of material and returnV the same to the outside drum.

After the "desired mixing and lblending has taken place and the machine is to be discharged, the direction' of rotatior` n! the drum is reversed. Upon reversal, the material in the drum outside the central tube then yis moved toward the lefthand or .feed-end of the machine, where the discharger inside the feed end will serve as a pickupr scoop. 'I'he helical night in the feed-anddischarge unit, together with the external scoop, will now operate to convey material out of the drum into the hopper, where it is discharged for delivery.-

said outer drum into said innerrcylinder and ak plurality of discharging means spaced axially on -said inner cylinder for discharging material from said inner cylinder to said outer drum.

2. In a mixing and blending machine, an outer revoluble drum, a unitarily mounted inner drum,

yhelical feeding conveyors yrigidly secured to the inner surfaces of saiddrums for progressively feeding material in opposite directions simultaneously, means fory feeding 'material from said outer drum into said inner drum and a plurality of axially spaced discharging means on said inner drum 'for discharging material from said inner dmm to said outer drum.

1 3. YIn a mixing and blending machine, unitarily mounted revoluble inner and outer drums, means 'rigidly secured to the'interior of said drums for ing means Vmounted on said inner drum for 'dis charging material from said inner to said outerl drum whereby the travel of said discharged material is reversed. y

4. In a mixing and blending machine, inner and outer co-axlal revoluble drums, each having helical conveyors rigidly mounted on their inner surfaces, the outer conveyor comprising nights which progressively increase in number at pref determined points from the supply end toward the discharge end of the outer drum, the inner conveyor comprising nights which progressively decrease in number at pre-determined points from the supply end toward the discharge end of the inner drum, means for feeding material from said outer drum into said inner drum and means for discharging material from said inner drum to said outer drum.

5. In a mixing and blending machine, unitarily mounted revoluble inner and outer drums, conveying means rigidly secured to the inner surfaces of said drums for simultaneously feeding material through said drums in opposite directions, said conveying means comprising progressively increasing and decreasing sectional flights from the supply ends of said drums, respectively, and means axially mounted on said inner drum at the points of decrease of the nights for discharging material from said inner to said outer drum.

6. In a mixing and blending machine, unitarily mounted revoluble inner and outer drums, conveying means rigidly mounted on the interior surfaces of said drums to progressively move material in said drums in opposite directions at the same time, said conveying means comprising a plurality of sectional progressively increasing and decreasing flights of blading, means for feeding material from said outer druminto said inner drum and means axially mounted on said inner drum at the points of decrease of the nights for discharging material from said inner to said outer drum, thereby reversing the direction of movement of the discharged material.

'7. The method of mixing and blending granular material which comprises conveying said material in one direction, dividing said material at certain points of its travel into an increasing number of portions, reversing the direction of travel of each said portion, successively decreasing the number of portions at predetermined points during the Yreversed movement, and causing each said reversed portion to be positively fed in the direction of its initial movement.

8. The method of mixing and blending granular material which comprises dividing said material into an increasing number of portions successively during the initial forward movement of said material, reversing the direction of now of all of said portions, and decreasing the number of said reversed portions successively at predetermined points of its travel by causing one of said reversed portions to unite with other material and be fed in the direction of said initial movement at each of said pre-determined points.

9. The method of mixing and blending granular material which comprises dividing an original stream of material into an increasing number of streams successively during the initial forward movement -of said material, reversing the direction of now of all of said streams, and decreasing the number of said reversed streams successively at pre-determined points of its travel by causing one of said reversed streams to unite with said original stream and be fed in the direction of said initial movement at each of said pre-determined points.

REGINALD JACKSON. 

